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Enabling Internet on BBB - Ubuntu Host

Enabling Internet on BBB when Host is Ubuntu

Boot your BBB and login.
ifconfig to check network interface configuration.
- eth0 - Physical Ethernet port
- usb0, usb1 - Ethernet over USB, come with static IP addresses
  - To see where these are configured, go to /opt/scripts/boot/ and there you will find two shell scripts:
    - autoconfigure_usb0.sh
    - autoconfigure_usb1.sh
    These will run during the booting process of the board and configure static IP addresses for usb0, usb1 interfaces.
Check the Network and see if you have the following Ethernet connection(s). The following should be detected automatically when you connect BBB to your Ubuntu host PC.

ethernet-over-usb

ifconfig-bbb

ifconfig-ubuntu

Now, try to ping between the two and see if there's any problem. (Should be no problem!)

BBB Settings

From BBB, run ping www.google.com, and it will tell Network is unreachable. We need to do some setting so that BBB can share Internet connection with the Ubuntu host.

From BBB, add following two lines (DNS servers) to /etc/resolv.conf. You may need sudo privilege to do this.


xxxxxxxxxx
4
1
/* /etc/resolv.conf */
2

3
nameserver 8.8.8.8
4
nameserver 8.8.4.4

From BBB, run sudo route add default gw 192.168.7.1 usb0 and sudo route add default gw 192.168.7.1 usb1 to add the IP's of the default gateways (which are essentially the IP addresses of Ubuntu host interfaces) to the routing table.

Ubuntu Host Settings

From Ubuntu host, do the following settings to share the Internet between Wifi and Ethernet.
1. Enabling IP forwarding
```
xxxxxxxxxx
1
1
echo 1 | sudo tee /proc/sys/net/ipv4/ip_forward
```
  For anyone not completely familiar with Linux, please note that Kiran is a root user in this video (Daniel has explained how to gain root access using sudo su above, note the command prompt now ends in #). If you do not have root privileges (your command prompt ends with a $ sign) you'll need to come at things a bit differently.
```
xxxxxxxxxx
1
1
echo 1 | sudo tee /proc/sys/net/ipv4/ip_forward
```
  Will set your IP forwarding flag. This command takes the output of echo and pipes it ( | is the pipe symbol) to the tee command, which can be run with elevated privileges and will therefore write to ip_forward. (The tee command simply writes to stdout and one or more files.)
  sudo can't be used directly with echo (i.e. sudo echo 1 > /proc/sys/net/ipv4/ip_forward will not work), as elevated privileges are not applied to the indirect ( > is the indirect symbol).
  You'll also need to run 'sudo /sbin/iptables' to get the IP forwarding commands to work. The iptables binary lives in the sbin folder, which contains system/admin binaries which are not available to ordinary users.
2. IP table setting
  This is basically the process to share Wifi (Ubuntu host is connected to) with Ethernet (interface the target will be communicating with Ubuntu host over USB).
```
xxxxxxxxxx
2
1
sudo iptables --table nat --append POSTROUTING --out-interface <wifi_interface> -j MASQUERADE
2
sudo iptables --append FORWARD --in-interface <ethernet_interface_to_share_with> -j ACCEPT
```
  Run ifconfig to find interface names. In my case:
  - <wifi_interface> - wlp61s0
  - <ethernet_interface_to_share_with> - enx3ce4b041b45a or enx3ce4b041b45d
Now, BBB should be able to ping www.google.com.
Also, try sudo apt update and see if get requests are successful!
If all successful, congratulations! Your BBB is now connected to Internet!

References

Nayak, K. (2022). Embedded Linux Step by Step Using Beaglebone Black [Video file]. Retrieved from https://www.udemy.com/course/embedded-linux-step-by-step-using-beaglebone/